The present invention relates, in general, to nuclear power plants. More particularly, the present invention pertains to an apparatus in which spent fuel rods from spent fuel assemblies may be consolidated for storage and to a method for consolidating spent fuel rods.
In a nuclear power reactor, fuel rods are typically held in a fuel assembly by a grid structure, which positions the fuel rods so that they are spaced from one another. Once a fuel assembly has been sufficiently used in the nuclear reactor, it is removed from the nuclear reactor and usually stored in a fuel pool in the nuclear power plant. The spent fuel assembly is radioactive, emitting alpha, beta, and gamma radiation; consequently, it generates decay heat. The water in the fuel pool removes some decay heat through free circulation. The water in the fuel pool also provides some shielding from the radiation emitted by the spent fuel assemblies in the pool. The spent fuel assemblies are located with sufficient spacing between them to preclude criticality.
Fuel pools in existing nuclear power plants were typically designed to accommodate spent fuel assemblies for interim storage only. The expectation was that reprocessing plants would be in service and that the spent fuel assemblies would be sent to such plants. However, such plants have not yet become operational. Furthermore, facilities for long-term storage of spent fuel assemblies on a large-scale basis are presently nonexistent. Accordingly, spent fuel assemblies are being stored in the fuel pools of nuclear power plants, and the available storage space in such pools is rapidly being consumed.
In order to provide more storage space in their fuel pools, many nuclear power plants have installed, or intend to install, racks in their fuel pools that will permit the fuel assemblies to be stored closer together. These racks are typically equipped with sheets of shielding material located between the fuel assemblies. The sheets of shielding material enable the fuel assemblies to be stored closer together without becoming critical. Conventional fuel pool racks, however, generally have insufficient storage capacity to accommodate the spent fuel assemblies and rods that will accumulate during the lifetime of a nuclear power plant.
Accordingly, a need exists for an uncomplicated, inexpensive apparatus in which spent fuel rods from spent fuel assemblies may be consolidated for storage after they have decayed sufficiently. Moreover, a need exists for a simple, efficient method for consolidating spent fuel rods.